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	<head>
		<title>three.js - WebGPU - Backdrop Area</title>
		<meta charset="utf-8">
		<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
		<link type="text/css" rel="stylesheet" href="example.css">
	</head>
	<body>

		<div id="info">
			<a href="https://threejs.org/" target="_blank" rel="noopener" class="logo-link"></a>

			<div class="title-wrapper">
				<a href="https://threejs.org/" target="_blank" rel="noopener">three.js</a><span>Backdrop Area</span>
			</div>

			<small>
				Backdrop area effect.
			</small>
		</div>

		<script type="importmap">
			{
				"imports": {
					"three": "../build/three.webgpu.js",
					"three/webgpu": "../build/three.webgpu.js",
					"three/tsl": "../build/three.tsl.js",
					"three/addons/": "./jsm/"
				}
			}
		</script>

		<script type="module">

			import * as THREE from 'three/webgpu';
			import { color, positionWorld, linearDepth, viewportLinearDepth, viewportSharedTexture, screenUV, hue, time, checker, uv, modelScale } from 'three/tsl';
			import { hashBlur } from 'three/addons/tsl/display/hashBlur.js';

			import { Inspector } from 'three/addons/inspector/Inspector.js';

			import { GLTFLoader } from 'three/addons/loaders/GLTFLoader.js';

			import { OrbitControls } from 'three/addons/controls/OrbitControls.js';

			let camera, scene, renderer;
			let mixer, clock;

			init();

			function init() {

				camera = new THREE.PerspectiveCamera( 50, window.innerWidth / window.innerHeight, 0.25, 25 );
				camera.position.set( 3, 2, 3 );

				scene = new THREE.Scene();
				scene.backgroundNode = hue( screenUV.y.mix( color( 0x66bbff ), color( 0x4466ff ) ), time.mul( 0.1 ) );
				camera.lookAt( 0, 1, 0 );

				clock = new THREE.Clock();

				const ambient = new THREE.AmbientLight( 0xffffff, 2.5 );
				scene.add( ambient );
			
				// model

				const loader = new GLTFLoader();
				loader.load( 'models/gltf/Michelle.glb', function ( gltf ) {

					const object = gltf.scene;
					mixer = new THREE.AnimationMixer( object );

					const action = mixer.clipAction( gltf.animations[ 0 ] );
					action.play();

					scene.add( object );

				} );

				// volume

				// compare depth from viewportLinearDepth with linearDepth() to create a distance field
				// viewportLinearDepth return the linear depth of the scene
				// linearDepth() returns the linear depth of the mesh
				const depthDistance = viewportLinearDepth.distance( linearDepth() );

				const depthAlphaNode = depthDistance.oneMinus().smoothstep( .90, 2 ).mul( 10 ).saturate();
				const depthBlurred = hashBlur( viewportSharedTexture(), depthDistance.smoothstep( 0, .6 ).mul( 40 ).clamp().mul( .1 ) );

				const blurredBlur = new THREE.MeshBasicNodeMaterial();
				blurredBlur.backdropNode = depthBlurred.add( depthAlphaNode.mix( color( 0x003399 ).mul( .3 ), 0 ) );
				blurredBlur.transparent = true;
				blurredBlur.side = THREE.DoubleSide;

				const depthMaterial = new THREE.MeshBasicNodeMaterial();
				depthMaterial.backdropNode = depthAlphaNode;
				depthMaterial.transparent = true;
				depthMaterial.side = THREE.DoubleSide;

				const checkerMaterial = new THREE.MeshBasicNodeMaterial();
				checkerMaterial.backdropNode = hashBlur( viewportSharedTexture(), .05 );
				checkerMaterial.backdropAlphaNode = checker( uv().mul( 3 ).mul( modelScale.xy ) );
				checkerMaterial.opacityNode = checkerMaterial.backdropAlphaNode;
				checkerMaterial.transparent = true;
				checkerMaterial.side = THREE.DoubleSide;

				const pixelMaterial = new THREE.MeshBasicNodeMaterial();
				pixelMaterial.backdropNode = viewportSharedTexture( screenUV.mul( 100 ).floor().div( 100 ) );
				pixelMaterial.transparent = true;

				// box / floor

				const box = new THREE.Mesh( new THREE.BoxGeometry( 2, 2, 2 ), blurredBlur );
				box.position.set( 0, 1, 0 );
				box.renderOrder = 1;
				scene.add( box );

				const floor = new THREE.Mesh( new THREE.BoxGeometry( 5, .01, 5 ), new THREE.MeshBasicNodeMaterial( {
					color: 0xff6600,
					opacityNode: positionWorld.xz.distance( 0 ).oneMinus().clamp(),
					transparent: true,
					depthWrite: false
				} ) );
				floor.position.set( 0, 0, 0 );
				scene.add( floor );

				// renderer

				renderer = new THREE.WebGPURenderer( /*{ antialias: true }*/ );
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( window.innerWidth, window.innerHeight );
				renderer.setAnimationLoop( animate );
				renderer.toneMapping = THREE.NeutralToneMapping;
				renderer.toneMappingExposure = .9;
				renderer.inspector = new Inspector();
				document.body.appendChild( renderer.domElement );

				const controls = new OrbitControls( camera, renderer.domElement );
				controls.target.set( 0, 1, 0 );
				controls.update();

				window.addEventListener( 'resize', onWindowResize );

				// gui

				const materials = {
					'blurred': blurredBlur,
					'depth': depthMaterial,
					'checker': checkerMaterial,
					'pixel': pixelMaterial
				};

				const options = { material: 'blurred' };
				box.material = materials[ options.material ];

				const gui = renderer.inspector.createParameters( 'Scene settings' );
				gui.add( box.scale, 'x', 0.1, 2, 0.01 ).name( 'box scale x' );
				gui.add( box.scale, 'y', 0.1, 2, 0.01 ).name( 'box scale y' );
				gui.add( options, 'material', Object.keys( materials ) ).onChange( name => {

					box.material = materials[ name ];

				} );

			}

			function onWindowResize() {

				camera.aspect = window.innerWidth / window.innerHeight;
				camera.updateProjectionMatrix();

				renderer.setSize( window.innerWidth, window.innerHeight );

			}

			function animate() {

				const delta = clock.getDelta();

				if ( mixer ) mixer.update( delta );

				renderer.render( scene, camera );

			}

		</script>
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